Method and apparatus for punching blanks from webs of sheetlike material



Oct. 15, 1968 HANS-GEORG BIELERT 3,405,830

METHOD AND APPARATUS FOR PUNCHING BLANKS FROM WEBS OF SHEETLIKE MATERIAL Filed Nov; 1, 1966 5 Sheets-Sheet 1 FIG.

J fir/tI-f Al ATTORNEY Oct. 15, 1968 HANS-GEORG BIELERT 3,405,880

METHOD AND APPARATUS FOR PUNCHING BLANKS FROM WEBS OF SHEETLIKE MATERIAL 5 Sheets-Sheet 2 Filed Nov 1, 1966 INVENTOR:

l/Il/j- 56026 3/5.! 6K7 Oct. 15, 1968 Filed Nov.

WEBS OF SHEETLIKE MATERIAL 5 Sheets-Sheet I5 A, ATTORNEY United States Patent 3,405,880 METHOD AND APPARATUS FOR PUNCH- ING BLANKS FROM WEBS 0F SHEET- LKKE MATERIAL Hans-Georg Bielert, Alferde, Kreis Hameln, Germany, as-

signor to Stephan-Werke G.m.b.H. & Co., Hameln (V /user), Germany Filed Nov. 1, 1966, Ser. No. 591,304- Claims priority, application Germany, Nov. 2, 1965, St 24,584 Claims. (Cl. 242-56.8)

The present invention relates to a method and apparatus for punching blanks from webs of sheet-like material. More particularly, the invention relates to a method and appauatus which may be utilized to subdivide elongated webs of metallic material into laminations of the type used in dynamos. Still more particularly, the invention relates to a punching method and apparatus which may be utilized for economical conversion of relatively wide and relatively long webs of sheet stock into laminations or other types of blanks.

In accordance with the presently prevailing practice, laminations for dynamos are formed by punching blanks out of rectangular sheets or bands. The stock is advanced lengthwise past a punching station where a single set or several sets of cooperating punching dies form laminations during dwells between successive stepwise advances of the stock. Such operation is rather uneconomical, not only because the originally produced sheet or band stock must be subdivided into widths which correspond to that of one or more laminations but also because the stock is not used up without waste in expensive material. Moreover, the provision of a battery of several sets of dies in a single punching apparatus contributes to the bulk, weight and initial cost so that such large apparatus are uneconomical, particularly in a medium-sized manufacturing plant. It was further found that the operation of conventional punching apparatus is uneconomical for the additional reason that the intervals between successive passes of sheet or band stock past the punching station are too long so that the output of such apparatus per unit of time is rather low.

Accordingly, it is an important object of my present invention to provide a very simple, economical and accurate method of mass-producing laminations or analogous blanks from metallic or nonmetallic web or sheet stock.

Another object of the invention is to provide a method according to which the intervals between successive passes of web or sheet stock past one or more sets of punching dies may be reduced to a minimum without in any way afiecting the accuracy and/or economy of the punching operation.

A further object of the invention is to provide a method of the just outlined characteristics according to which a web of sheet stock can be subdivided into blanks without any waste or with a minimum of waste.

An additional object of the invention is to provide a method of mass-producing dynamo laminations or other types of blanks by repeatedly passing a web or strip past a punching station and in such a way that the component parts of the punching means are subjected to balanced stresses and undergo minimal wear.

Still another object of the instant invention is to provide a novel and improved punching apparatus which may be utilized in the practice of the above outlined method.

A further object of the invention is to provide the punching apparatus with novel web advancing and guiding means.

An additional object of the invention is to provide a "ice novel punching means which may be utilized in the above outlined apparatus.

Another object of the invention is to provide a punching apparatus which can operate practically continuously to subdivide into individual blanks a web or strip of sheet material despite the fact that the width of the original web is a multiple of the width of a blank and that the apparatus comprises only one or at most two sets of punching dies.

Still another object of the present invention is to provide a punching apparatus which can be readily converted for processing of wider or narrower webs consisting of metallic or other material, wherein at least some operations can be carried out in a fully automatic way, and which can be converted to produce blanks of different sizes or shapes.

Briefly stated, one feature of the present invention resides in the provision of a method of punching blanks from elongated webs whose width is a multiple of the width of a blank, particularly for punching armature punchings or laminations from elongated sheets of metallic material. The method comprises the steps of advancing an elongated web lengthwise along a predetermined path so that one end of the web is leading and that at least one marginal portion of the Web travels past a punching station, separating blanks from successive increments of the one marginal portion while such increments dwell at the punching station whereby the one marginal portion yields a series of blanks and is at least substantially consumed with resulting narrowing of the web, placing at least one marginal portion of the thus narrowed web into registry with the punching station, advancing the thus narrowed web lengthwise past the pundhing station, preferably in such a way that the other end of the web is leading but that the web advances in the same direction as the ori mal Web, and separating blanks from successive increments of the one marginal portion of the narrowed web. The same steps can be repeated again and again, depending on the width of the original web and also whether or not the blanks are being separated from one or both marginal portions of the web.

That end of the web which is leading is preferably convoluted onto a reel in a region located downstream of the punching station. The narrowed web can be moved sideways 'with reference to the punching station to place the latter into registry with one of its marginal portions, or the punching station can be moved transversely of the narrowed web.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved punching apparatus itself, however, both as to its construction and its mode of operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawings, in which:

FIG. 1 is a somewhat schematic side elevational view of a punching apparatus which embodies one form of the present invention;

FIG. 2 is a somewhat schematic top plan view of the punching apparatus; and

FIG. 3 is a schematic elevational view of a duplex punching unit which forms part of a modified punching apparatus.

Referring to the drawings in detail, and first to FIGS. 1 and 2, there is shown a punching apparatus which comprises three basic components, namely a punching means 2 mounted on a substantially C-shaped frame member, 4a, composite guide means for guiding an elongated web 13 of metallic sheet stock lengthwise and including a pair of reels or spools 7, 8 rotatable about the axes of horizontal shafts 6 which extend at right angles to the direction of lengthwise movement of the web 13, and a feed including motors 30, pulleys 31 on the shafts 6, and endless belts 32. The construction of the feed is such that the reel 7 can be driven independently of the reel 8, or vice versa. The frame member 4a is mounted on a base plate 1 which further carries a second frame member or column 4 for inverting means including a two-armed lever whose arms carry the shafts 6 for the reels 7, 8. The lever 5 is fulcrumed at 5a so that it can be rotated about a horizontal axis in order to change the positions of the reels 7 and 8. The motors 30 are mounted on the lever 5.

The punching means 2 is constituted by a punching press of conventional design and includes upper and lower dies 3 one of which is reciprocable by a motor 33. A transmission 34 serves to transmit motion from the output shaft of the motor 33 to the upper die 3.

The aforementioned guide means further includes a deflecting roller 11 which is mounted on a third frame member 10, and more particularly on a horizontal platform 35 which supports an intermediate portion of the web 13. The roller 11 cooperates with a presser roll 11a. A further portion of the web is supported by guide elements 36, 37 mounted on the frame member 4a. The base plate 1 supports a control stand 12 which accommodates several control elements serving to operate various components of the apparatus in a predetermined sequence.

Each of the reels 7, 8 has two flanges 9 at least one of which is adjustable axially of the respective shaft 6 so that the edge faces of the Web 13 are accurately guided when the one or the other motor 30 is started in order to advance the web from the core of the reel 7 onto the core of the reel 8, or vice versa.

The operation is as follows:

In the position shown in FIGS. 1 and 2, the reel 7 constitutes a supply reel and its core carries a supply of convoluted we-b stock whose width is a multiple of the width of a single blank. The width of a blank corresponds to the width of one of the seven strips 14 shown in FIG. 2, each such strip being subdivisible into a series of discrete blanks in response to dwell of successive increments of the web 13 at the punching station, namely, in the gap between the dies 3 of the punching means 2. The flanges 9 of the reels 7, 8 are adjusted in such a way that the distance between the flanges of the supply reel 7 equals the width of the web 13 and that the distance between the flanges of the reel 8 (which constitutes a takeup reel) equals the width of the web 18 minus the width of a strip 14. Such adjustment of the flanges 9 insures that the web 13 is properly guided in respose to starting of the motor 30 for the takeup reel 8. In response to stepwise lengthwise advance of the web 13, its upper marginal portion 14A (as viewed in FIG. 2) advances past the punching means 2 whereby the dies 3 cooperate with each other and subdivide the marginal portion 14A into a series of discrete blanks, for example, into laminations usable in a dynamo. Such laminations are also called armature punchings. When the motor 30 for the takeup reel 8 is in operation, the web 13 advances along a first limit switch 15, along the guide element 36, across the gap between the dies 3, along the guide element 37, along a second limit switch 16, around the deflecting roller 11, along the platform 35, and is convoluted onto the core of the takeup reel 8 downstream of the punching station as considered in the direction of movement of the web. The marginal portion 14A is used up, either substantially or in its entirety, so that the core of the takeup reel 8 collects a narrower web 13A. When the reel 8 has collected and convoluted the entire web 13A, the motor 30 for the reel 8 is arrested and the lever 5 is pivoted to move the empty reel 7 into the space previously occupied by the reel 8, i.e., the reel 7 becomes the takeup reel and the reel 8 becomes the supply reel. The flanges 9 of both reels are adjusted so that the marginal portion 14B of the narrower web 13A is placed into registry with the punch- 4- ing station (gap between the dies 3) and the leading end of the web 13A is attached to the core of the reel 7. The distance between the flanges of the reel 7 is reduced to that of the width of the web 13 minus the combined width of two strips 14. During threading of the web 13A between the dies 3, these dies may separate from the marginal portion 14B a series of blanks so that the width of the leading end of the web 13A is reduced sufliciently to fit between the flanges 9 of the reel 7.

The operator then starts the motor 30 for the reel 7 (which is now the takeup reel) and the marginal portion 14A is subdivided into a second series of blanks. The same procedure is carried a total of seven times because the original web 13 has a width corresponding to the combined width of seven blanks. It will be seen that the web 13 or 13A invariably advances in the same direction, namely, as indicated in FIG. 1 by arrow 38. However, the leading end of the web 13 becomes the trailing end of the narrower web 13A, and the trailing end of the web 13A becomes the leading end of the still narrower web which is obtained in response to subdivision of the marginal portion 14B into a series of discrete blanks. Proper adjustment of flanges 9 prior to each starting of one of the motors 30 is desirable to insure that the web cannot run at a bias and that each of the seven strips 14 can yield the same number of equally dimensioned punched blanks. As stated before, the apparatus of FIGS. 1 and 2 can be operated in a fully automatic way in accordance with a predetermined program. The limit switches 15, 16 form part of the programming means and can be used to automatically arrest one of the motors 30, to arrest the motor 33 for the upper die 3, and/or to initiate or terminate certain other operations of the apparatus. The apparatus may further comprise suitable servomotors (not shown) which can move the flanges 9 axially of the respective shafts 6 and one of such servomotors may be used to pivot the lever 5 in automatic response to completed winding of the web onto the core of the reel 7 or 8. Of course, the programming system comprises several additional control elements in the form of switches or the like which are not shown in the drawings.

FIG. 3 illustrates a portion of a modified punching apparatus. This modified apparatus includes different punching means including two sets of punching dies 18 and 19 mounted symmetrically with reference to a vertical symmetry plane 40. The web 13 is indicated by phantom lines and is advanced stepwise in a direction at right angles to the plane of FIG. 3. The sets of dies 18 and 19 are movable or shiftable toward and away from each other in directions indicated by a double-headed arrow 41 so that they may simultaneously form two rows of blanks by subdividing both marginal portions of the Web 13. The width of the web 13 is preferably n times the width of a blank wherein n is an odd number (for example, seven) so that, in response to repeated passage of the web 13 between the dies 18, 19, there remains a single strip 14 whose width equals the width of a single blank. This remaining strip 14 is then placed into registry with the dies 18 or 19 so that one set of dies is idle when the punching means is to form the last series of blanks. Such selection of the width of the web 13 results in substantial savings in web material because the dies 18 and 19 cannot be placed into immediate proximity of each other and, therefore, some waste material would remain if the last pass of the web would take place while the width of the web would at least equal the combined width of two blanks. In other words, the original width of the web 13 would be n times the width of a strip 14 plus a fraction of such unit width to account for the necessary minimum spacing between the dies 18 and 19.

The punching means of FIG. 3 has been found to be particularly useful in mass-production of dynamo laminations or analogous blanks. The wear on its parts is less pronounced because the stresses upon the dies 18, 19 are symmetrical. The numeral 17 denotes a gantry-like frame member for the dies 18, 19. The motor 133 serves to eciprocate the upper dies 15, 19 through the intermediary of a transmission 134.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features which fairly constitute essential characteristics of the generic and specific aspects of my contribution to the art, and therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is:

1. A method of punching blanks from elongated webs whose width is a multiple of the width of a blank, comprising the steps of advancing an elongated web lengthwise along a predetermined path so that one end of the web is leading and that at least one marginal portion of the web travels past a punching station; separating blanks from successive increments of said one marginal portion while such increments dwell at said punching station whereby said one marginal portion yields a series of blanks and is at least substantially consumed with resulting narrowing of the web; placin at least one marginal portion of the thus narrowed web into registry with the punching station; advancing the thus narrowed web lengthwise past said punching station; and separating blanks from successive increments of said last named marginal portion.

2. A method as defined in claim 1, further including reversing the direction of advance of the narrowed web so that the other end of the web is leading.

3. A method as defined in claim 1, further comprising the step of convoluting the leading end of the web downstream of said punching station.

4. A method as defined in claim 1, wherein said web is a sheet of metallic material and said blanks are constituted by armature punchings for dynamos.

5. A method as defined in claim 1, wherein the step of placing at least one marginal portion of the narrowed web into registry with the punching station includes moving the narrowed web sideways with reference to the punching station.

6. A method as defined in claim 1, wherein the step of placing at least one marginal portion of the narrowed web into registry with the punching station includes moving the punching station transversely of the narrowed web.

7. A method as defined in claim 1, wherein at least said first mentioned separating step includes separating blanks from successive increments of both marginal portions of the web and wherein said punching station is movable transversely of the web.

8. A method as defined in claim 7, wherein the width of said web is n times the width of a blank and wherein n is an odd number.

9. A method as defined in claim 1, wherein said advancing steps include moving the web intermittently by increments at least approximating the length of a blank.

10. Apparatus for punching blanks from elongated webs whose width is a multiple of the width of a blank, comprising punching means operative to separate blanks from a web; a feed for moving an elongated web lengthwise so that one end of the web is leading; and guide means for guiding the web in a predetermined path so that at least one marginal portion of the web moves past said punching means and the punching means separates blanks from successive increments of said one marginal portion while such increments register with said punching means whereby the one marginal portion yields a series of blanks and is at least substantially consumed with resulting narrowing of the web, at least one of said means being movable With reference to the other means in a direction transversely of said predetermined path so that at least one marginal portion of the thus narrowed web can be placed into registry with said punching means prior to movement of the narrowed web past said punching means to yield another series of blanks.

11. Apparatus as defined in claim 10, wherein said guide means comprises a first reel for supporting the web in convoluted condition upstream of said punching means and a second reel for collecting the one end of the Web downstream of said punching means, as considered in the direction of lengthwise movement of the web.

12. Apparatus as defined in claim 11, wherein said reels are rotatable about axes making right angles with the direction of lengthwise movement of the web and wherein at least one of said reels is shiftable in parallelism with the respective axis.

13. Apparatus as defined in claim 11, further comprising inverting means for changing the position of said reels subsequent to collection of the narrowed web on said second reel.

14. Apparatus as defined in claim 13, wherein said inverting means comprises a two-armed lever turnable about a fixed axis, each of said reels being rotatably supported by one arm of said lever.

15. Apparatus as defined in claim 11, wherein each of said reels comprises at least one axially movable flange.

16. Apparatus as defined in claim 10, wherein said guide means is movable with reference to said punching means.

17. Apparatus as defined in claim 10, wherein said punching means is movable with reference to said guide means.

18. Apparatus as defined in claim 17, wherein said punching means comprises two punching units each operative to separate blanks from one marginal portion of the web, said punching units being movable toward and away from each other in a direction transversely of said predetermined path.

19. Apparatus as defined in claim 17 for separating blanks from webs Whose Width is n times the width of a blank wherein n is an odd number, wherein said punching means comprises two punching units each operative to separate blanks from one marginal portion of the web, said punching units being movable toward and away from each other transversely of said predetermined path.

20. Apparatus as defined in claim 11, wherein said feed includes means for rotating said reels independently of each other.

References Cited UNITED STATES PATENTS 485,485 11/1892 Brada 83-35 X 1,536,027 4/1925 Mortimer 8332 X 2,224,070 12/1940 Walter 83--649 3,113,741 12/1963 Herr 24256.8

ANDREW R. IUHASZ, Primary Examiner. 

1. A METHOD OF PUNCHING BLANKS FROM ELONGATED WEBS WHOSE WIDTH IS A MULTIPLE OF THE WIDTH OF A BLANK, COMPRISING THE STEPS OF ADVANCING AN ELONGATED WEB LENGTHWISE ALONG A PREDETERMINED PATH SO THAT ONE END OF THE WEB IS LEADING AND THAT AT LEAST ONE MARGINAL PORTION OF THE WEB TRAVELS PAST A PUNCHING STATION; SEPARATING BLANKS FROM SUCCESSIVE INCREMENTS OF SAID ONE MARGINAL PORTION WHILE SUCH INCREMENTS DWELL AT SAID PUNCHING STATION WHEREBY SAID ONE MARGINAL PORTION YIELDS A SERIES OF BLANKS AND IS AT LEAST SUBSTANTIALLY CONSUMED WITH RESULTING NARROWING OF THE WEB; PLACING AT LEAST ONE MARGINAL PORTION OF THE THUS NARROWED WEB INTO REGISTRY WITH THE PUNCHING STATION; ADVANCING THE THUS NARROWED WEB LENGTHWISE PAST SAID PUNCHING STATION; AND SEPARATING BLANKS FROM SUCCESSIVE INCREMENTS OF SAID LAST NAMED MARGINAL PORTION. 